Copolymerization with azo catalyst of 2-phenyl allyl alcohol and styrene and solid copolymers thereof



United States Patent 3,536,684 COPOLYMERIZATION WITH AZO CATALYST OFZ-PHENYL ALLYL ALCOHOL AND STYRENE AND SOLID COPOLYMERS THEREOF JosephA. Verdol, Dolton, and Marc 0. Thienot, Park Forest, 11]., assignors toSinclair Research, Inc., New York, N .Y., a corporation of Delaware NoDrawing. Filed Apr. 4, 1967, Ser. No. 628,282 Int. Cl. C08f l/76, 21/02U.S. Cl. 26088.1 14 Claims ABSTRACT OF THE DISCLOSURE Copolymers ofstyrene and 2-phenyl allyl alcohol are obtained by reacting fromapproximately l-SO moles of styrene per mole of 2-phenyl allyl alcoholin the presence of an azo group-containing catalyst. This polymerizationreaction may be carried out using various techniques such as suspension,bulk or solution polymerization. Suspension polymerization is anespecially eflicient method. A solid copolymer having a ratio of 2 to 1moles of styrene per mole of 2-phenyl allyl alcohol is especiallyobtained.

This invention relates to a method of copolymerizing styrene and2-phenyl allyl alcohol. In a particular aspect, it relates to the use ofan azo group-containing catalyst in the copolymerization of styrene and2-phenyl allyl alcohol.

Polymers of allyl alcohols are, in general diffcult to prepare. Resinousmaterials produced by the conjoint polymerization of styrene and2-phenyl allyl alcohol have been described in the prior art, e.g., inUS. Pat. 2,563,611 to Mills et al., issued Aug. 7, 1951. Thepolymerization techniques which have been described as operable for thepreparation of this copolymer have been limited, however, to mass andaqueous emulsion polymerization systems. Furthermore, the catalystsemployed have been limited to a select group of peroxide catalysts,including sodium peroxide, benzoyl peroxide and hydrogen peroxide.Benzoyl peroxide has been disclosed as the preferred catalyst of thisgroup.

The styrene-2-phenyl allyl alcohol copolymers have been of limitedinterest, however, due to the extremely low yields resulting from theuse of the above polymeriza- 1 tion techniques. The poor yields,furthermore, are more in evidence as one attempts to prepare copolymershaving relatively high concentrations of combined 2-phenyl allylalcohol. Since, to a great extent, the usefulness of the copolymers liesin their ability to enter into further reactions through their pendanthydroxyl groups, for instance, to cross-link other resin systemscontaining hydroxyl-reactive functional groups, such as epoxy resins,phenolformaldehyde resins, urea-formaldehyde resins and the like, thedisadvantages of the inability to effectively produce copolymers of high2-phenyl allyl alcohol-to-styrene ratios are readily apparent. The arthas heretofore only been successful in preparing styrene-phenyl allylalcohol copolymers having a maximum combined phenyl allyl alcoholcontent of about 30 weight percent. Copolymers of such low hydroxylconcentration are vastly hampered in their ability to react with andmodify, e.g., cure hydroxyl-reactive resins such as the epoxy resins.

It has now been found that significantly higher yields of copolymers ofstyrene and 2-phenyl allyl alcohol may be obtained through the use, aspolymerization catalyst, of a minor, effective amount of an azogroup-containing compound. In addition, attendant advantages found inthe use of an azo catalyst are the ability to prepare copolymers havingrelativel high ratios of 2-phenyl allyl alcohol-to-styrene, e.g., ofabout 1:1 to 2:1 molar ratios 3,536,684 Patented Oct. 27, 1970 ofcombined styrene to 2-phenyl allyl alcohol, equivalent to weightpercentages of styrene in the range of 44-61% and of Z-phenyl allylalcohol in the range of 39-56%. A further advantage of employing anazo-type catalyst is the ability to employ with almost equaleffectiveness various polymerization systems, including bulk, solutionand suspension polymerizations. The molar ratio of 2- phenyl allylalcohol monomer to styrene monomer in the reaction mixture can be about1:1 to 1:2, although approximately 1-50 moles of styrene per mole of2-phenyl allyl alcohol can be in the reaction mixture.

The azo type catalysts employed in the polymerization of the presentinvention include the symmetrical azocompounds having an azo group,N'=N, bonded from each of the nitrogen atoms to tertiary carbon atoms.The azo compounds can be represented by the structure:

wherein R is an aliphatic, including cycloaliphatic, hydrocarbon of upto about 11 carbon atoms with the total carbon atoms on each side of theazo group being about 4 to 11 and Z is selected from the groupconsisting of wherein R is lower alkyl, say of 1 to 6 carbon atoms. Rand R in the structural formula may be saturated or unsaturated,straight or branched chain. The preferred catalysts are the alpha,alpha-azobis alkane-nitriles.

Illustrative of suitable azo type catalysts are alpha,alpha-azodiisobutyronitrile; alpha, alpha'-azobis (alpha, gammadimethylvaleronitrile); alpha, alpha azobis (alphamethylbutyronitrile);alpha, alpha-azobis (alphaethyl butyronitrile); alpha, alpha'azobis(alpha-phenylpropionitrile); alpha, alpha'-azobis(alpha-cyclopropylpropionitrile); alpha, alpha'-azobis(alpha-cyclohexylpropionitrile); alpha, alpha-azobis(alpha-cycloheptylpropionitrile); alpha, alpha-azobis(alpha-isopropyl-betamethylbutyronitrile); alpha, alpha"-azobis (alpha,gammadimethyl-capronitrile); alpha, alpha'-azobis-(alpha-nbutyl-capronitrile); alpha, alpha'-azobis(alpha-isobutylgamma-methylvaleronitrile); alpha, alpha'-azobis(alphamethyl-gamma-carboxy-butyronitrile) and its salts, e.g., disodiumgamma, gamma'-azobis-(gamma-cyanovalerate);1,1'-azodicyclohexanecarbonitrile; 1,1-azodicycloheptanecarbonitrile;1,l'-azobis (3-methylcyclopentanecarbonitrile); 1,1-azobis(2,4-dimethylcyclohexanecarbonitrile), and the corresponding amides andesters of the above in which the nitrile group or groups are replaced byamide and/or ester groups, e.g., to give alpha, alphaazodiisobutyramide;alpha, alpha'-azobis (alpha, gammadimethylvaleramide); alpha,alpha'-azobis (alpha-cyclopropylpropionamide); 1,1 azodicyclohexanecarbonamide; N,Nalpha, alpha'-azodiisobutyrodimethylamide; dimethyl,diethyl and dihexyl-alpha, alpha'-azodiisobutyrate. The concentration ofthe catalyst may vary with the temperature selected and with theparticular polymerization system, i.e., Whether bulk, solution,suspension or emulsion polymerization, but in all cases will be incatalytically elfective amounts. Generally, the catalyst concentrationswill fall in the range of about 0.1 to 10 3 percent by weight of themonomeric reactants, preferably about 1 to percent by weight of themonomers.

Polymerization temperatures may be from about 20 C., to about 200 C.,while temperatures in the range from 45 C., to 80 C., are preferred.

Copolymers containing a molar ratio of Z-phenyl allyl alcohol (Z-PAA) tostyrene of from about 1:1 to 1:50 may be prepared by the method of thepresent invention. Most often the desired ratio of 2-PAA to styrene willbe from 1:2 to 1:10. Copolymers of styrene and Z-phenyl 4 to 2-PAA,solid polymers, melting point circa 126-136 C. and molecular weight ofabout 4000, were formed. Infrared analysis showed these polymers tocontain one Z-PAA unit per 4-5 styrene units.

Azobisisobutyronitrile was much more effective than benzoyl peroxide forbulk copolymerization. At a 1% catalyst level and 1:1 mole ratio ofmonomers, up to 58% conversion was realized. With 5% of the azo catalystthe conversion increased to 90%. The copolymers formed withazobisisobutyronitrile at the 1:1 monomer ratio were allyl alcohol areobtained by reacting from approximately white solids having maximummeltlng points of 162178 1-50 moles of styrene per mole of 2-phenylallyl alcohol C. Molecular Weights ranged from 1800-2900. Infrared inthe presence of an azo group-containing catalyst. A analysis showed thepolymers to be 1:1 copolymers (2- solid copolymer having a ratio of 2 to1 moles of styrene PAAzstyrene). per mole of Z-phenyl allyl alcohol isespecially obtained. At a 1:5 molar ratio of monomers (Z-PAAzstyrene) Asstated previously, various polymerization techniques withazobisisobutyronitrile catalyst, copolymers of 115 may be employedsuccessfully with the azo catalyzed sysmolar composition were obtainedat near quantitative tern of the present invention. Suspensionpolymerization, yield. Using a 1% catalyst concentration the copolymershowever, has proven to be the most efiicient method for were solids,melting at 140162 C., with a molecular producing copolymers of 2-PAA andstyrene, as will be weight from 5500 to 6900. Using a 5% catalystconcenevidenced by the examples to follow. tration the copolymers weresolids with melting point The following examples are drawn to the use ofthree ranges of 118-158 C. and molecular Weights of 2800 to differentpolymerization techniques, namely: bulk, solu- 4200. Infrared analysisshowed the polymers to be 1:5 tion and aqueous suspensionpolymerization, for the prepcopolymers. aratlon of Z-PAA-styrenecopolymers using the catalyst EXAMPLE II s01ufiOn polymerization systemof the present invention. S I 1 outron po ymerizations in benzene wereconducted Example IBulk Polymenzatlon in 350-ml. pressure bottles at10-33% combined monomer The bulk copolymerization experiments werecarried concentration. In a typical experiment 26 grams of 2- out in 75ml. polymerization tubes. Combined monomer 30 phenyl allyl alcohol, 41grams of styrene, 137 grams of charges ranging from 17-50 grams wereadded, with the benzene and 0.68 grams (1%) azobisisobutyronitrileappropriate catalyst, to the polymerization tubes which catalyst werecharged to the polymerization bottle. The were flushed with nitrogen andsealed. The tubes were bottle was flushed with nitrogen, sealed andheated in a heated to the appropriate temperatures for the timeslaunderometer bath at 60 C. for 65 hours. shown. When the reactionmixtures were liquid, methanol The products were worked up by partiallyevaporating was added to precipitate the polymers. When solid polythebenzene and adding methyl ethyl ketone in an amount meric products wereobtained, they Were dissolved in just suflicient to redissolved thepolymer. Methanol was methyl ethyl ketone and subsequently precipitatedby the then employed to precipitate the polymer, which was filadditionof methanol. The products were then dried in tered and dried in vacuo at100-110 C. to constant vacuo at 100l10 C. weight.

The bulk polymerizations were performed with an azo As in the bulkpolymerization experiments, the effeccatalyst according to the method ofthe present invention, tiveness of the azo catalyst in solutionpolymerization was and with a peroxide catalyst, according to the methodof compared with that of the recommended peroxide catathe prior art. Theformer was OC, OC-azobisisobutyronilyst of the prior art, benzoylperoxide. trile; the latter, benzoyl peroxide. Conditions and results 5Conditions and results of the solution copolymerizaof the experimentsare recorded in Table 1, below. tions are given in Table II.

TABLE I Molar ratio in Reaction conditions copolymer by IR Catalyst andconcentration, 2-PAAzstyrene Percent Copolymer analysis 2-PAA:

percent mole ratio conversion M.P. 0. M01. wt. Temp. C. Time hrs.styrene azobisisobutyronitrile, 1 1:1 41 142-150 1, 800 80 o In 58162-178 2, 425 60 Azobisisobutyronitrile, 5 1:1 44. 5 148-154 2, 500 80o 1:1 90 161-167 2,906 Azobisisobutyronitrile, 1 1:5 80 129-140 6, 90080 o 1:5 94 140-162 5,505 Azobisisobutyrom 1: 5 72 118-125 2, 801 80 Do1:5 97 138-158 4,216 60 Benzoyl peroxide, 1. 1:1 7. 3 80 Benzoylperoxide, 5-- 1:1 8. 5 168-186 4,800 80 Benzoyl peroxide, 1- 1:5 49131-136 4, 400 80 Benzoyl peroxide, 5 1:6 68 126-132 3, 000 80 Theresults of the bulk polymerization experiments, The results of thesolution polymerization experiments, illustrated in Table I, demonstratethat with 1% benzoyl as reported in Table II, are evidence of theeffectiveness peroxide at a 1:1 molar ratio of Z-PAA to styrene, 7.3% ofthe azo type catalysts for the copolymerization of 2- conversion oftotal monomers to solid polymer occurred. FAA and styrene while insolution, and convincingly show At 5% benzoyl peroxide concentration,the conversion was 8.5%. Infrared analysis showed the copolymers to be1:1 (mole ratio) copolymers. The 1:1 copolymers with benzoyl peroxidehad molecular weights of about 4800.

the inferiority of benzoyl peroxide as a catalyst for this method ofpolymerization. The copolymers produced with the azo catalysts weresolids melting above 100 C., and their compositions (monomer ratios),conformed closely With benzoyl peroxide at a 5:1 molar ratio of styreneto the composition of the monomers charged. Polymerization reactionsconducted in benzene at 60 C., gave tion of the monomer ratios andcatalyst concentrations higher conversions than reactions conducted at80 C. used.

TABLE II R t d Molar rrfitio eac ion con itions 01 mer yI Catalyst andconcentration, Q-PAAzstyreno, Percent Copolynier 515 515, 2-PAA: percentmole ratio conversion M.P., 0. M01. wt. Temp., C. Time, hrs. styrene.Azobisisobutyronitrile, 1 1:1 8 80 12 1:1 Do 1; 1 70 141-164 1, 914 s0s5 1 1 Azol]o)isisobutyronitrlle, 5.-

127-148 1, 467 60 65 o z 80 12 Azobisisobutyronitrile, 1 1:2 56 136-1522, 207 60 65 1:2 Azobisisobutyronitrile, 5- 1:2 82 137-148 2, 235 60 651:2 Do 1 2 61 122-134 1, s52 60 e5 1 2 Do 1: 2 64 118-130 1, 816 e0 65 12 Azobisisodutyronitrile, 1.... 1:3 46 109-127 2, 050 60 12 1:2-1z3Azobisisodutyronitrile, 5 1:3 62 110-124 1, 830 80 12 1:2-113Azobisisodutyronitrile, 1 1:5 43 129-139 3, 937 B0 12 1:5Azobisisodutyronltrile, 5.. 1: 5 18 124-132 2, 788 80 12 1:5 Benzoylperoxide, 0.5"..- 1:1 60 60 Benzoyl peroxide, 1 1:1 60 60 EXAMPLEIIISuspension polymerization In most cases the ol mers were isolated inthe form P Suspension polymerization experiments shown in Table of ifeaslly dried m vacupm III were carried out in 350-ml. pressure bottlesat 33% g 6 p0 ymeirs 8; uce y d i g g f monomer concentration using 3%polyvinyl alcohol g unquesnonady 3; easl y an e an 1 (based on monomerweight) as the suspending agent. In 2 i m u g i fi 1 9: a typicalexperiment, a combined monomer charge of 50 a e ac d preifirlce O 1 i ay e grams of styrene and 60 grams of 2-phenyl allyl alcohol S an lmpun yunng e copo ymenza Ion 0 s yrene was added to the pressure bottlecontaining 136 grams of and 2.'phenyl allyl alcohol was also Studled' Indistilled water, about 2 grams of polyvinyl alcohol susghgx ense r56%ad:i1:((11 tL0?:2OIE1it-Ilf1fl1gl gllylleghllogliflei pending agent andthe appropriate amount of catalyst alcohol and st ene Chlorine anal :i sshow ed that tile The pressure bottle was flushed with nitrogen, sealedand majorit of g um was g Grated in the o1 g z in a rotatinglaunderometar bath at 60 for mer. A lthough no g i eat reduction inconversion wa s ours. Azobisisobutyronitrile provide to be superior tothe pernotlqed a product Shghfly lower m 1 we.1ght was oxide catalyst inthe bulk and solution Polymerization ex- 30 2353 i y gg g i zg g 13:periments. Suspension polymerization is, in reality, a chlorisge fi gmore u f heatin thanpco g form of bulk polymerization. In suspensionpolymerizare fired Without the chlode im p0 y tion a protective colloidis employed to promote disperp 3 the foregoing examples is arent thatthe Sim} of the liquid monomer Into tlny.dmplets' E l 40 use of an azogroup-containing catalyst Edithe co 01 m- 18 then polymeiizeli to formSohd p Olymer.1c.p amcle' erization of styrene and 2-phenyl allylalcohol pr ddd ces Smce the Polymenzatlon Occuls h dropletilt 1S advanconsistently higher yields of copolymer regardless of the tageous toemploy a catalyst WhlCh is soluble 1n the mon- 01 merization s Stem m 10ed thanth t d d b fmers being g azobisisobutsgofiligfli cat3- ben oylperoxid e catali ze d pol ymerizatizn the iatte r stwasver soueintemonomersan a teav antage of n t being readily susceptible toradical-induced bemg the method Preferred by the Pnor In addltlondecomposition. by employing the polymerization technique of the instantTable III summarizes in detail the results of several lnventloncopolymers havl ng fe y y conflellcopolymerization experiments atvarying mole ratios of tmtlon than heretofore attalned, havlng combmed2-PAA to styrene, e.g., 1:1, 1:2, 1:3, 1:4 and 1:5. These molar 113110of Styrene to 2131161134 allyl alcohol in the experiments were conductedat C., and at 33% monorange of 1:1 to 2:1, may be prepared; and suchcopolymer concentration in water. mers exhibit greatly enhancedreactivity with the afore- TABLE III Molar ratio in Reaction conditionscopolymer by IR Catalyst and concentration, 2-PAAzstyrene, PercentCopolymer analysis, Z-PAA: percent mole ratio conversion M.P., 0. M01.wt. Temp., C. Time, hrs. styrene Azobisisobutyronitrile, 1 1:1 61 89-104540 60 G5 1;1 Azobisisobutyronitrile, 5-.- 1:1 98 155-157 1, 443 60 6511 Azobisisobutyronitrile, 1- 1:2 111-155 1, 222 60 e5Azobisisobutyronitrile, 5. 1:2 99 117-158 1,910 60 65 1:2Azobisisobutyronitrile, 1- 1:3 94 126-156 5,016 60 65 1;3Azobisisobutyronitrile, 5 1:3 99 129-154 2, 339 60 65 1;3Azobisisobutyronitrile, 1. 1:5 96 125-158 4,571 60 65 1:5Azobisisobutyronitrile, 5. 1:5 112-144 2, 545 60 65 1; 5 0 1; 2 99109-146 1, 688 60 5 1 Do 1=2 99 -149 1,840 60 e5 1;

1 Addition of 5% of 2-phenyl allyl chloride.

2 Addition of 10% 01 2-pheny1 allyl chloride.

As evidenced by Table III in comparison with data mentionedhydroxyl-reactive resins, enabling them to in the other examples,suspension polymerization proved, efiectively modify such resins,whereas copolymers hereby far, to be the most efiicient method forproducing 70 tofore prepared by the prior art peroxide-catalyzedcocopolymers of 2-PAA and styrene. Conversion of monopolymerization havebeen comparatively ineffective. mers to polymer generally exceeded 90%.A complete When employing azo-catalyzed solution, suspension or familyof copolymers vary ng in mole who from 1:1 to emulsion polymerizationsystems, appropriate solvents, 1:5 was prepared at molecular weightsranging from 540 reaction vessels, emulsion and suspension aids,solventto 6757. The molecular weights were found to be a func- 75monomer ratios, etc., may be selected in accordance with the teachingsand techniques well known in the polymer art.

It is claimed:

1. In the copolymerization of styrene and 2-phenyl allyl alcohol, theimprovement which comprises the use as the copolymerization catalyst ofa minor, effective amount of an azo catalyst in contact with a reactionmixture of from about 1:1 to 1:50 molar ratio of 2-phenyl allyl alcoholto styrene in bulk, solution or aqueous suspension at a temperature ofabout 20 to about 200 C.

2. The process of claim 1 wherein the azo catalyst is present in thereaction medium in an amount from about 0.1 to 10 percent by weight ofthe styrene and 2-phenyl allyl alcohol.

3. The process of claim 2 wherein the copolymerization is carried out inan aqueous suspension.

4. The process of claim 2 wherein the copolymerization is conducted attemperatures of from 45 C. to 80 C.

5. The process of claim 1 wherein the azo groupcontaining compound hasthe structure:

Z z R( 3N=N-( 1R it it wherein R is an aliphatic hydrocarbon of up toabout 11 carbon atoms with the total carbon atoms on each side of theazo group being about 4 to 11, and Z is selected from and wherein R islower alkyl.

6. The method of claim 5 wherein R is alkyl and Z is CN.

7. The method of claim 1 wherein the catalyst is alpha,alpha-azobisisobutyronitrile.

8. In the copolymerization of styrene and 2-phenyl allyl alcohol whereinthe molar ratio of 2-pheny1 allyl alcohol monomer to styrene monomer inthe reaction mixture is from about 1:1 to 1:50, the improvement whichcomprises conducting said copolymerization in an aqueous suspension attemperatures from about 20 C., to about 200 C., in the presence of acatalytic amount of alpha, alpha-azobisisobutyr0nitrile.

9. The process of claim 8 wherein the molar ratio of 2-phenyl allylalcohol monomer to styrene monomer is about 1:1 to 1:2.

10. The process of claim 1 wherein the molar ratio of Z-phenyl allylalcohol monomer to styrene monomer is about 1:1 to 1:2.

11. A process for preparing copolymers of 2-phenyl allyl alcohol andstyrene which comprises polymerizing the monomers 2-phenyl allyl alcoholand styrene in molar ratios of about 1:1 to 1:2 in bulk, solution oraqueous suspension at a temperature of 45 C. to C. in the presence offrom about 1 to 5% of an azo catalyst based on said monomers andobtaining as the resulting product a solid copolymer of Z-phenyl allylalcohol and styrene having a molar ratio of 2-phenyl allyl alcohol tostyrene of about 1:1 to 1:2.

12. A process for preparing copolymers of Z-phenyl allyl alcohol andstyrene as set forth in claim 11 wherein said azo catalyst is alpha,alpha-azobisisobutyronitrile.

13. A process for preparing copolymers of 2-phenyl allyl alcohol andstyrene as set forth in claim 11 wherein the monomers 2-phenyl allylalcohol and styrene are in molar ratio of about 1:1 and the resultingproduct is a polid copolymer of Z-phenyl allyl alcohol and styrenehaving a molar ratio of Z-phenyl allyl alcohol to styrene of about 1:1.

14. A process for preparing copolymers of 2-phenyl allyl alcohol andstyrene as set forth in claim 13 wherein said azo catalyst is alpha,alpha-azobisisobutyronitrile.

References Cited UNITED STATES PATENTS 2,563,611 8/1951 Mills et a1.26088.1 2,940,946 6/1960 Shokal et a1 260-23 3,299,021 1/ 1967Denchfield 260-881 3,401,213 9/1968 Trementozzi et a1. 260880 OTHERREFERENCES Alfrey, Bohrer, and Mark. Copolymerization. IntersciencePress, New York (1952) pp. 5 and 6.

JOSEPH L. SCHOFER, Primary Examiner J. C. HAIGHT, Assistant Examiner US.Cl. X.R.

